The light curtain: what are they and how do they work?

In 1951, optometrist, engineer, and inventor, Erwin Sick (1909-1988) patented his inventions; photoelectric sensors and the autocollimation. These inventions provided the technology behind light curtains. Today, they are used in manufacturing, processing, and the automotive industry, to name a few, and have numerous applications. As we venture into the future their use will increase, in more fields, but what are they and how do they work? Let’s take a closer look.


A light curtain is an optoelectronic device. They are also known as safety light screens or safety light barriers. Their main purpose is safety. They can be used to set off an alarm or to shut down machinery if the light curtain has been obstructed by anything, such as a body part. Depending on what your needs are they can detect small objects entering a smaller area, or large things entering large spaces. They can go across a machinery opening or across warehouse doorways. Traditional safety barriers are solid objects that block the path, but they can be moved, reached over, and nor can the control the equipment. Light curtains can be programmed so no access through the curtain is permitted, or they can allow materials to pass through in certain places. Once again, it is all based on what your company’s needs are as to how light curtains can benefit your business the most.


The technology that Sick invented, involved creating a device where light (usually infra-red beams) is projected from a transmitter to a receiver, or the beams can be reflected back with mirrors. With light curtains you place the 2 components at opposite sides of the space you want to protect. If you are in manufacturing, then your machines have moving parts. Most may be safely shielded, but probably not all of them. By placing a light curtain across the exposed area, anytime a worker puts their hands, or whatever else, through the light curtain a signal is sent to the machinery. Within a fraction of a second it shuts down and can’t be restarted until the workspace is empty again. In the case of an automated warehouse light curtains can be placed across all warehouse entry points, preventing your automated system from working once the threshold has been crossed.


Knowing where to buy light curtains for your business is more important then getting the right curtain for the right project, and of course that is extremely important. With a reputable dealer you can ensure you get excellent advice, and you only buy quality products. Don’t guess which setup is right for your business, ask the professionals at RS.

Now that you know what light curtains are and how they work, it’s time to implement them in your business. Increase the safety for your machine operators, and maintenance crews, and boost your productivity with less downtime. Contact the team at RS and get the right, expert advice from a reputable dealer and then buy the correct, quality light curtains for you business’s needs.

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